On the restore disks there should be another installer titled something along the lines of "Additional Software Restore" or "Optional Software Restore" (I don't recall the name precisely and am away from my Restore disks... ) to accomplish that. From within that you can choose which of the applications that shipped with your Mac that you want to install.
Of course that is assuming that you formatted and reinstalled the operating system using the restore disks that came with your computer and not a retail boxed version of the OS- since the retails disks do not come with iLife included.